This invention is in the field of biomedical devices, and relates generally to implantable devices for sensing parameters associated with a target tissue and/or for actuating a target tissue. Methods for making, implanting, and using the implantable biomedical devices are provided.
Implantable biomedical devices have potential for a range of important clinical applications, such as treatment and/or monitoring of neurological disorders (e.g., epilepsy and Parkinson's disease), heart disorders (e.g., arrhythmias), vascular disorders, muscular and/or nerve disorders (e.g., as brain-computer interfaces for controlling prosthetics). Efficacious use of implantable biomedical devices, however, is dependent in part upon design strategies that provide compatibility between the hard, planar surfaces of conventional integrated circuits and medical devices and the soft, curvilinear tissues of biological systems. Overcoming this physical mismatch is important because differences in form traditionally lead to low fidelity coupling at the biotic/abiotic interface and limited long-term tissue health in connection with some conventional implantable devices.
Attempts to improve device-tissue coupling have in some cases sacrificed electronic performance by moving away from conventional silicon-based electronic components to amorphous silicon, organic or hybrid organic-inorganic semiconductors, which exhibit electronic properties, such as field effect mobilities, on/off ratios, etc., significantly inferior to corresponding single crystalline silicon-based devices. While such amorphous silicon and organic-based materials may be electronically inferior to singe crystalline silicon, they do have certain properties useful for biomedical applications, such as flexibility, chemically biocompatibility and, in some cases, biodegradability.
Recently, a number of patents and publications have disclosed implantable, biodegradable devices. For example, International Patent Application Publication WO 2008/085904 discloses biodegradable electronic devices that may include a biodegradable semiconducting material and a biodegradable substrate. International Patent Application Publication WO 2008/108838 discloses biodegradable devices for delivering fluids and/or biological material to tissue. International Patent Application Publication WO 2008/127402 discloses biodegradable sensors containing embedded biological materials. International Patent Application Publication WO 2008/103464 discloses medical devices having nanostructured surfaces, which are optionally coated with a biodegradable polymer. Similarly, International Patent Application Publication WO 99/45860 discloses devices having biocompatible, and optionally resorbable, substrates with projections that, depending on their spacing, either promote or discourage cell adhesion.
Other patents and publications have disclosed implantable electronic devices. For example, U.S. Pat. No. 5,403,700 discloses devices having polyimide substrates supporting patterned metal conductors. U.S. Pat. No. 7,190,051 discloses hermetically packaged and implantable electronics fabricated using silicon-on-insulator technology. International Patent Application Publications WO 2009/111641 and WO 2009/114689 disclose stretchable and flexible electronic devices and sensor arrays.